Types of Abstracts
There are mainly two types of abstracts,i.e.，descriptive and informative abstracts.Most writers now prefer to provide informative abstracts in their work.
2.1 Descriptive Abstract
A descriptive abstract outlines the topics covered in a piece of writing,so the reader can decide whether to read the entire paper or not.In many ways,the descriptive abstract is like a table of contents in paragraph form.It makes no judgments about the work,nor does it provide results,conclusions,or recommendations of the research.It incorporates key words found in the text and may include the background,purpose,and focus of the research.Nevertheless,due to its descriptive rather than substantive nature,it can seldom serve as a substitute for the whole paper.Descriptive abstracts are usually very short-100 words or less.
Example of Descriptive Abstract
Background:Language is the vehicle and symbol of culture,while culture is the root and core of language.College English teaching,serving as a platform for students to increase cross-linguistic knowledge and cross-cultural competence, should integrate aspects of language and culture.
Particular Focus:Reviewing and analyzing the major literature on cross-cultural college English teaching（2001—2010),this paper makes an attempt to build a structure mode and a practice mode of cross-cultural college English teaching.
Purpose:It aims at improving college students'cross-cultural sensitivity, inclusiveness and flexibility,extending cultural influence of college English teaching, and developing soft power of colleges.（Kong Deliang&Luan Shuwen,Foreign Langue World,2012.02)
In this example,the abstract provides the information about the background, particular focus,and purpose.Sentence one and two introduces the background of college English teaching.Sentence three presents particular focus of the paper （building a structure mode and a practice mode of cross-cultural college English teaching).Sentence four tells the purpose.
2.2 Informative Abstract
An informative abstract provides details about the substance of a piece of writing because readers will sometimes rely on the abstract alone for information.It does not simply describe what will be in the paper,but also gives a summary of the main factual information,such as your methods and materials,results,conclusions and recommendation.Therefore,the readers can often get an overview of the whole paper only after reading an informative abstract.Nowadays,this type of abstract is used as a“heading”in most journals.The length of informative abstract varies according to discipline,from a paragraph to a page or two,but it is rarely more than 10%of the length of the entire work.
Informative abstract generally follows this format:an explanation of the title, the purpose of the research,how the research was conducted,what the main findings were,and what they mean,what recommendations can be made for further research,and what the implication or limitation of the research was.
Example 1
Background:Surface Plasmon（SP)technologies exploit the spectral and spatial properties of collective electronic oscillations in noble metals placed in an incident optical field.Yet the SP local density of states（LDOS),which rule the energy transducing phenomena between the SP and the electromagnetic field,is much less exploited.
Purpose:Here,we use two-photon luminescence（TPL)microscopy to reveal the SP-LDOS in thin single-crystalline triangular gold nanoprisms produced by a quantitative one-pot synthesis at room temperature.Variations of the polarization and the wavelength of the incident light redistribute the TPL intensity into twodimensional plasmonic resonator patterns that are faithfully reproduced by theoretical simulations.
Results:We demonstrate that experimental TPL maps can be considered as the convolution of the SP-LDOS with the diffraction-limited Gaussian light beam.
Conclusions:Finally,the SP modal distribution is tuned by the spatial coupling of nanoprisms,thus allowing a new modal design of plasmonic information processing devices.（Viarbitskaya et al.,Nature Materials,2013)
Example 2
Purpose:This paper presents a study exploring the efficacy of Wikis in an online language exchange program involving a purposeful sample of university students from China and the UK.The article first provides a brief overview of the use of Web 2.0 applications in language education.It then specifically addresses the potential advantages of using Wikispaces in second language acquisition,particularly in tasks designed for the purpose of collaborative learning.
Methods:Research methods employed in the study included questionnaire, interview and analysis of textual input on Wikis.Participants were students from two partner universities in China and the UK,who communicated with each other in English and Chinese to discuss curriculum-based topics posted to the China-UK Wikispaces.
Results:The results demonstrate that tasks designed for Wikis offer students constructive opportunities to communicate with each other and develop their language proficiencies.
Conclusion:The findings also indicate that the informed involvement of language tutors in selecting topics and designing tasks is instrumental in effectively facilitating and further enhancing students'experiences of collaborative learning on Wikis.（Zou Bin et al.,Chinese Journal of Applied Linguistics,2012.01)
From the above two examples,it can be found that the informative abstract provides not only the information about background,purpose or methods,but also results or conclusions.By reading the informative abstract,the readers can get the overview and key points of the whole paper.
2.3 Differences between Descriptive and Informative Abstracts
Both types of abstract must communicate ideas effectively,preferably with direct,active statements in short,simple sentences.There can be some differences:
